Context: Many medical schools include group reflection in their curriculum, and many researchers have considered both the concept and the outcomes of reflection. However, no research has been carried out on how ‘reflective talk’ is structured in the classroom. This paper describes how tutors and residents organise group reflection sessions in situ by describing an example of group reflection in medical education. Our aim is to provide an evidence base that can be used by medical educators to think about the way reflection should be included in their curriculum. Methods: We video-recorded 47 group reflection sessions of the general practice postgraduate training course at Erasmus University Medical School, Rotterdam. We used conversation analysis to unravel their overall structural organisation: the way participants organise and structure a conversation. Through micro-analysis of the moment-to-moment unfolding of group reflection, we distinguished the main building blocks that form the architecture of these sessions. Results: We found that participants consistently oriented towards the following activity types: significant event, reason for sharing, learning issue and learning uptake. There was variation in the order of the activity types, the amount of time spent on each of them, and how they were accomplished. By studying reflection in its messy social context, we found order, commonalities and patterns that were typical of the architecture of group reflection in this setting, even if no formal structure is prescribed. Conclusions: In ‘Exchange of Experience’, the overall structural organisation consisted of activity types through which a case becomes shared, reflectable, learnable and valuable. There are essential discrepancies between cognitive reflection models and the reality of the classroom. Being conscious of this overall structural organisation can be a tool for tutors of these groups to help them navigate from one activity to another or to diagnose what is not working in the group discussion.